通过注册的 TLB 从 python 访问未注册的 COM 对象

Posted 2023-03-29

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【中文标题】通过注册的 TLB 从 python 访问未注册的 COM 对象【英文标题】：Accessing unregistered COM objects from python via a registered TLB 【发布时间】：2011-03-07 22:48:52 【问题描述】：

我目前正在使用三段代码：

一个闭源应用程序 (Main.exe) 作为 dll (comobj.dll) 实现的闭源 VB COM 对象我正在用 Python 开发的代码

comobj.dll 托管一个我想从 Python 中使用的 COM 对象（可以说是“MainInteract”）。我已经可以从 IronPython 完美地使用这个对象，但由于其他要求，我需要从常规 Python 使用它。我认为这里最好的方法是使用 win32com，但我根本无法取得任何进展。

首先，一些可用的 IronPython 代码：

import clr
import os
import sys

__dir__ = os.path.dirname(os.path.realpath(__file__))
sys.path.insert(0, __dir__)
sys.path.append(r"C:\Path\To\comobj.dll") #This is where the com object dll actually is

clr.AddReferenceToFileAndPath(os.path.join(__dir__, r'comobj_1_1.dll')) #This is the .NET interop assembly that was created automatically via SharpDevelop's COM Inspector

from comobj_1_1 import clsMainInteract

o = clsMainInteract()
o.DoStuff(True)

现在是我在常规 Python 中尝试的代码：

>>> import win32com.client
>>> win32com.client.Dispatch("11111111-comobj_guid_i_got_from_com_inspector")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line 95, in Dispatch
    dispatch, userName = dynamic._GetGoodDispatchAndUserName(dispatch,userName,clsctx)
  File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line 104, in _GetGoodDispatchAndUserName
    return (_GetGoodDispatch(IDispatch, clsctx), userName)
  File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line 84, in _GetGoodDispatch
    IDispatch = pythoncom.CoCreateInstance(IDispatch, None, clsctx, pythoncom.IID_IDispatch)
 pywintypes.com_error: (-2147221164, 'Class not registered', None, None)

我也尝试过使用 TLB 的友好名称：

>>> import win32com.client
>>> win32com.client.Dispatch("Friendly TLB Name I Saw")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line 95, in Dispatch
dispatch, userName = dynamic._GetGoodDispatchAndUserName(dispatch,userName,clsctx)
  File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line 104, in _GetGoodDispatchAndUserName
return (_GetGoodDispatch(IDispatch, clsctx), userName)
  File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line 84, in _GetGoodDispatch
    IDispatch = pythoncom.CoCreateInstance(IDispatch, None, clsctx, pythoncom.IID_IDispatch)
pywintypes.com_error: (-2147221005, 'Invalid class string', None, None)

事实上，我唯一的成功是：

import pythoncom
tlb = pythoncom.LoadRegTypeLib("11111111-comobj_guid_i_got_from_com_inspector",1,1,0)
>>> tlb
<PyITypeLib at 0x00AD7D78 with obj at 0x0025EDF0>
>>> tlb.GetDocumentation(1)
(u'clsMainInteract', None, 0, None)

但我不确定如何从那里获取对象。我认为我的问题是我需要将 dll 加载到我的进程中并让它自己注册到我的进程的 COM 源中，这样我就可以正确地 CoCreateInstance / win32com.client.Dispatch() 就可以了。

我还看到Activation Contexts 被引用，尤其是在谈论“无注册 COM”时，但通常在诸如“如果您在 .manifest 文件中指定正确的内容，Windows 将为您创建上下文”这样的句子中。如果可能的话，我想避免清单文件，因为在与（封闭源）COM 对象 dll 相同的文件夹中需要一个文件，如果可以避免的话，我宁愿不删除该目录中的任何文件。

感谢您的帮助。

【问题讨论】：

我不知道答案在我的脑海中，但如果你能用 C++ 做到这一点，那么你可以相当简单地包装它。嗯，是的，我想这是一个选择，但我希望避免它。 【参考方案1】：

我访问免费下载管理器的类型库的操作如下：

import pythoncom, win32com.client

fdm = pythoncom.LoadTypeLib('fdm.tlb')
downloads_stat = None

for index in xrange(0, fdm.GetTypeInfoCount()):
    type_name = fdm.GetDocumentation(index)[0]

    if type_name == 'FDMDownloadsStat':
        type_iid = fdm.GetTypeInfo(index).GetTypeAttr().iid
        downloads_stat = win32com.client.Dispatch(type_iid)
        break

downloads_stat.BuildListOfDownloads(True, True)
print downloads_stat.Download(0).Url

上面的代码将打印第一次下载的 URL。

【讨论】：

【参考方案2】：

这是我设计的从 DLL 加载 COM 对象的方法。它基于大量关于 COM 等的阅读。我对最后几行不是 100% 确定，特别是 d=。我认为只有在传入 IID_Dispatch 时才有效（您可以查看是否为默认参数）。

此外，我相信这段代码会泄漏 - 一方面，DLL 永远不会被卸载（使用 ctypes.windll.kernel32.FreeLibraryW），而且我相信初始类工厂的 COM 引用计数会减少 1，因此永远不会被释放。但是，这仍然适用于我的应用程序。

import pythoncom
import win32com.client
def CreateInstanceFromDll(dll, clsid_class, iid_interface=pythoncom.IID_IDispatch, pUnkOuter=None, dwClsContext=pythoncom.CLSCTX_SERVER):
    from uuid import UUID
    from ctypes import OleDLL, c_long, byref
    e = OleDLL(dll)
    clsid_class = UUID(clsid_class).bytes_le
    iclassfactory = UUID(str(pythoncom.IID_IClassFactory)).bytes_le
    com_classfactory = c_long(0)
    hr = e.DllGetClassObject(clsid_class, iclassfactory, byref(com_classfactory))
    MyFactory = pythoncom.ObjectFromAddress(com_classfactory.value, pythoncom.IID_IClassFactory)
    i = MyFactory.CreateInstance(pUnkOuter, iid_interface)
    d = win32com.client.__WrapDispatch(i)
    return d

【讨论】：

链接不再可用更新链接：gist.github.com/ebnull/4219140【参考方案3】：

有关包装 object-from-DLL 情况的有用实用程序模块以及其他情况，请参阅https://gist.github.com/4219140

__all__ = (
    ####### Class Objects

    #CoGetClassObject - Normal, not wrapped
    'CoDllGetClassObject', #Get ClassObject from a DLL file

    ####### ClassFactory::CreateInstance Wrappers

    'CoCreateInstanceFromFactory', #Create an object via IClassFactory::CreateInstance
    'CoCreateInstanceFromFactoryLicenced', #Create a licenced object via IClassFactory2::CreateInstanceLic

    ###### Util

    'CoReleaseObject', #Calls Release() on a COM object

    ###### Main Utility Methods

    #'CoCreateInstance', #Not wrapped, normal call
    'CoCreateInstanceLicenced', #CoCreateInstance, but with a licence key

    ###### Hacky DLL methods for reg-free COM without Activation Contexts, manifests, etc
    'CoCreateInstanceFromDll', #Given a dll, a clsid, and an iid, create an object
    'CoCreateInstanceFromDllLicenced', #Given a dll, a clsid, an iid, and a license key, create an object
)

IID_IClassFactory2 = "B196B28F-BAB4-101A-B69C-00AA00341D07"

from uuid import UUID
from ctypes import OleDLL, WinDLL, c_ulong, byref, WINFUNCTYPE, POINTER, c_char_p, c_void_p
from ctypes.wintypes import HRESULT
import pythoncom
import win32com.client

import logging
log = logging.getLogger(__name__)


def _raw_guid(guid):
    """Given a string GUID, or a pythoncom IID, return the GUID laid out in memory suitable for passing to ctypes"""
    return UUID(str(guid)).bytes_le

proto_icf2_base = WINFUNCTYPE(HRESULT,
    c_ulong,
    c_ulong,
    c_char_p,
    c_ulong,
    POINTER(c_ulong),
)
IClassFactory2__CreateInstanceLic = proto_icf2_base(7, 'CreateInstanceLic', (
    (1, 'pUnkOuter'),
    (1 | 4, 'pUnkReserved'),
    (1, 'riid'),
    (1, 'bstrKey'),
    (2, 'ppvObj'),
    ), _raw_guid(IID_IClassFactory2))

#--------------------------------
#--------------------------------

def _pc_wrap(iptr, resultCLSID=None):
    #return win32com.client.__WrapDispatch(iptr)
    log.debug("_pc_wrap: %s, %s"%(iptr, resultCLSID))
    disp = win32com.client.Dispatch(iptr, resultCLSID=resultCLSID)
    log.debug("_pc_wrap: %s (%s)", disp.__class__.__name__, disp)
    return disp

def CoCreateInstanceFromFactory(factory_ptr, iid_interface=pythoncom.IID_IDispatch, pUnkOuter=None):
    """Given a factory_ptr whose interface is IClassFactory, create the instance of clsid_class with the specified interface"""
    ClassFactory = pythoncom.ObjectFromAddress(factory_ptr.value, pythoncom.IID_IClassFactory)
    i = ClassFactory.CreateInstance(pUnkOuter, iid_interface)
    return i

def CoCreateInstanceFromFactoryLicenced(factory_ptr, key, iid_interface=pythoncom.IID_IDispatch, pUnkOuter=None):
    """Given a factory_ptr whose interface is IClassFactory2, create the instance of clsid_class with the specified interface"""
    requested_iid = _raw_guid(iid_interface)

    ole_aut = WinDLL("OleAut32.dll")
    key_bstr = ole_aut.SysAllocString(unicode(key))
    try:
        obj = IClassFactory2__CreateInstanceLic(factory_ptr, pUnkOuter or 0, c_char_p(requested_iid), key_bstr)
        disp_obj = pythoncom.ObjectFromAddress(obj, iid_interface)
        return disp_obj
    finally:
        if key_bstr:
            ole_aut.SysFreeString(key_bstr)

#----------------------------------

def CoReleaseObject(obj_ptr):
    """Calls Release() on a COM object. obj_ptr should be a c_void_p"""
    if not obj_ptr:
        return
    IUnknown__Release = WINFUNCTYPE(HRESULT)(2, 'Release', (), pythoncom.IID_IUnknown)
    IUnknown__Release(obj_ptr)

#-----------------------------------

def CoCreateInstanceLicenced(clsid_class, key, pythoncom_iid_interface=pythoncom.IID_IDispatch, dwClsContext=pythoncom.CLSCTX_SERVER, pythoncom_wrapdisp=True, wrapas=None):
    """Uses IClassFactory2::CreateInstanceLic to create a COM object given a licence key."""
    IID_IClassFactory2 = "B196B28F-BAB4-101A-B69C-00AA00341D07"
    ole = OleDLL("Ole32.dll")
    clsid_class_raw = _raw_guid(clsid_class)
    iclassfactory2 = _raw_guid(IID_IClassFactory2)
    com_classfactory = c_void_p(0)

    ole.CoGetClassObject(clsid_class_raw, dwClsContext, None, iclassfactory2, byref(com_classfactory))
    try:
        iptr = CoCreateInstanceFromFactoryLicenced(
                factory_ptr = com_classfactory,
                key=key,
                iid_interface=pythoncom_iid_interface,
                pUnkOuter=None,
        )
        if pythoncom_wrapdisp:
            return _pc_wrap(iptr, resultCLSID=wrapas or clsid_class)
        return iptr
    finally:
        if com_classfactory:
            CoReleaseObject(com_classfactory)

#-----------------------------------------------------------
#DLLs

def CoDllGetClassObject(dll_filename, clsid_class, iid_factory=pythoncom.IID_IClassFactory):
    """Given a DLL filename and a desired class, return the factory for that class (as a c_void_p)"""
    dll = OleDLL(dll_filename)
    clsid_class = _raw_guid(clsid_class)
    iclassfactory = _raw_guid(iid_factory)
    com_classfactory = c_void_p(0)
    dll.DllGetClassObject(clsid_class, iclassfactory, byref(com_classfactory))
    return com_classfactory

def CoCreateInstanceFromDll(dll, clsid_class, iid_interface=pythoncom.IID_IDispatch, pythoncom_wrapdisp=True, wrapas=None):
    iclassfactory_ptr = CoDllGetClassObject(dll, clsid_class)
    try:
        iptr = CoCreateInstanceFromFactory(iclassfactory_ptr, iid_interface)
        if pythoncom_wrapdisp:
            return _pc_wrap(iptr, resultCLSID=wrapas or clsid_class)
        return iptr
    finally:
        CoReleaseObject(iclassfactory_ptr)

def CoCreateInstanceFromDllLicenced(dll, clsid_class, key, iid_interface=pythoncom.IID_IDispatch, pythoncom_wrapdisp=True, wrapas=None):
    iclassfactory2_ptr = CoDllGetClassObject(dll, clsid_class, iid_factory=IID_IClassFactory2)
    try:
        iptr = CoCreateInstanceFromFactoryLicenced(iclassfactory2_ptr, key, iid_interface)
        if pythoncom_wrapdisp:
            return _pc_wrap(iptr, resultCLSID=wrapas or clsid_class)
        return iptr
    finally:
        CoReleaseObject(iclassfactory2_ptr)

【讨论】：

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